/***************************************************************************

        TITLE:                engine.c
        
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        FUNCTION:        dummy engine routine

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        MODULE STATUS:        incomplete

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        GENEALOGY:        This is a renamed navion_engine.c originall written by E. Bruce 
                                Jackson
                                

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        DESIGNED BY:        designer
        
        CODED BY:        programmer
        
        MAINTAINED BY:        maintainer

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        MODIFICATION HISTORY:
        
        DATE        PURPOSE                                                BY

        CURRENT RCS HEADER INFO:

$Header$

 * Revision 1.1  92/12/30  13:21:46  bjax
 * Initial revision
 * 

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        REFERENCES:

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        CALLED BY:        ls_model();

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        CALLS TO:        none

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        INPUTS:

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        OUTPUTS:

--------------------------------------------------------------------------*/
#include <math.h>
#include "ls_types.h"
#include "ls_constants.h"
#include "ls_generic.h"
#include "ls_sim_control.h"
#include "ls_cockpit.h"
#include "c172_aero.h"

extern SIM_CONTROL        sim_control_;

void c172_engine( SCALAR dt, int init ) {
    
    float v,h,pa;
    float bhp=160;
        
    Throttle[3] = Throttle_pct;

    
    if ( ! Use_External_Engine ) {
        /* do a crude engine power calc based on throttle position */
        v=V_rel_wind;
        h=Altitude;
        if(V_rel_wind < 10)
            v=10;
        if(Altitude < 0)
            h=0;
        pa=(0.00144*v + 0.546)*(1 - 1.6E-5*h)*bhp;
        if(pa < 0)
            pa=0;

        F_X_engine = Throttle[3]*(pa*550)/v;
    } else {
        /* accept external settings */
    }

    /* printf("F_X_engine = %.3f\n", F_X_engine); */

    M_m_engine = F_X_engine*0.734*cbar;
    /* 0.734 - estimated (WAGged) location of thrust line in the z-axis*/

}


